Early prediction of ecotoxicological side effects of pharmaceutical impurities based on open-source non-testing approaches

Despite the increasing efforts to limit waste and avoid environmental contaminants, a large number of compounds using in the pharmaceutical field may have an ecotoxicological impact. Nevertheless, a complete overview of all possible ecotoxicological effects of pharmaceuticals is missing: that is especially true for chemical impurities. The lacking information regarding environmental behavior of impurities could be faced by computational techniques: the ability to predict the unknown toxicity of a compound can reduce uncertainties regarding possible negative effects on the environment of pharmaceutical impurities. In the current scenario, non-testing methods may answer to the requirement of assessing the ecotoxicological impact of chemicals in a more affordable way. For this purpose, in the first part of the review, definition and classification of chemical impurities are proposed, while in the second part, a description of four open-source computational tools (T.E.S.T., VEGA, LAZAR, and QSAR Toolbox) is provided after a brief survey of the computational methods. The paper also shows the advantages of combining individual test methods in order to increase confidence in the predictive results.